Peritoneal dialysis with various ways of performing it has established its position in the treatment of kidney patients. Its advantages over other dialysis methods include simplicity of the method itself and patient security. However, peritoneal dialysis is not as yet used as often as it could in view of its potential possibilities. A reason for this is the slowness and inefficiency of the present peritoneal dialyzers in view of e.g. hemodialysis, a single treatment taking unreasonably long time.
The object of the apparatus of this invention is to make it possible to perform peritoneal dialysis quickly, effectively and at the same time in completely controlled manner, whereby changes in a patient's fluid balance and disturbances in the flow of fluid can be taken into consideration. The apparatus as such must be applicable to conventional periodical peritoneal dialysis as well as to so-called continuous flow dialysis in which, by means of a double-catheter or two regular catheters, fluid is continuously maintained in motion in a patient's abdominal cavity.
On the above basis, the present invention relates to a peritoneal dialyzer, comprising a dialysis fluid vessel, a vessel for used fluid, a scales for weighing the vessels, a tubing system between the vessels and a patient, at least one pump for pumping the dialysis fluid into a patient, a valve (or a pump) for controlling the amount of dialysis fluid to be removed from a patient, and a control unit which is connected so as to be controlled by the scales and in turn controls the pump and the valve (or another pump).
Finnish Patent Publication No. 48674 discloses a peritoneal dialyzer in which, in order to determine the fluid balance, the dialysis fluid vessel and the used fluid vessel are weighed together. Dialysis fluid is passed from the vessel into a patient by means of static fluid pressure controlled by a valve which again is controlled by a scales. However, the static fluid pressure and resulting flow rate varies according to the degree of filling and size of the vessel. This could be eliminated by using a pump for such fluid supply but, on the other hand, the use of a pump leads to a substantial safety hazard unless the pressure of the fluid delivered into a patient is restricted one way or the other.